How a Democratic Dark-Money Group Flooded the 2018 House Map

BRADENTON BEACH, Fla. — The billboard flickered from the side of a truck, displaying an image of Representative Vern Buchanan, Republican of Florida, wearing a yachtsman’s cap. Keith Fitzgerald, a local dignitary invited by the group Floridians for a Fair Shake, stood before it as he tore into the lawmaker’s record.

The congressman embodied “deep and profound corruption,” Mr. Fitzgerald told a thin crowd. The nautical caricature of Mr. Buchanan, a wealthy auto dealer, alluded to his purchase of a multimillion-dollar yacht on the same day he voted for a bill cutting upper-income tax rates.

Floridians for a Fair Shake has criticized Mr. Buchanan for months, with paid advertising, campaign workers, and events like this, on a recent Sunday in a beachside parking lot. Yet Mr. Fitzgerald, a former Democratic state legislator and something of the guest of honor, confessed, “Honestly, I don’t know a whole lot about this group.”

“They told me what they were doing,” he continued. “I’m not sure where the money comes from.”

A structure unknown even to some of those involved, Floridians for a Fair Shake and 13 other groups around the country are funded and coordinated out of a single office in Washington, with the goal of battering Republicans for their health care and economic policies during the midterm elections.

At the center of the effort is an opaquely named Democratic organization, the Hub Project, which is on track to spend nearly $30 million since 2017 pressuring members of Congress in their districts. The great bulk of its funding has come from so-called dark money — funds from donors who are not legally required to reveal their names.

With that money, the Hub Project — run by a former Obama administration official and public relations specialist, Leslie Dach, and Arkadi Gerney, a former political strategist for the liberal Center for American Progress — set up an array of affiliate groups around the country, many with vaguely sympathetic names like Keep Iowa Healthy, New Jersey for a Better Future and North Carolinians for a Fair Economy. The Hub Project then used them to mobilize volunteers and run advertising on policy issues against Republican members of Congress many months before the election.